The use of antimicrobial agents plays an important role in current medical therapy. This is particularly true in dermatology where the most effective course of treatment for skin, mucous membrane, or hair lesions or infections frequently includes the use of a topical antimicrobial agent. The present invention is a topical antimicrobial composition, in the form of an aqueous gel or an aqueous lotion, which provides outstanding broad spectrum antimicrobial performance. The antimicrobial performance of the compositions of the present invention is superior to that of similar compositions formulated in a more conventional manner, such as creams, ointments, non-aqueous lotions or non-aqueous gels.
Various carboxylic acids are known to be effective antimicrobial agents; however, there is nothing in the art which would lead to the formulation of these compounds as aqueous gels or lotions, as opposed to more conventional product forms. Thus, for example, Keeney, Bull. Johns Hopkins Hosp., 78, 333 (1946), teaches that sodium caprylate (sodium octanoate) is an effective fungistat, useful in the treatment of moniliasis. The sodium octanoate is taught to be useful in the form of an aqueous solution, ointment, jelly or powder, all of which have a pH of about 7.4. No general preference is taught for any one form of administration over another, except that the powder form is preferred over the jelly for vaginal use, since it is suggested to be less irritating. U.S. Pat. No. 2,466,663, Russ, et al., issued Apr. 5, 1949, teaches that mixtures of caprylic acid and caprylic acid salts are effective antimicrobial/antifungal agents over a wide pH range (pH=4.5-10.5). These compositions are taught to be useful topically when formulated in a variety of conventional ways having a pH within the broad useful range, the precise pH depending upon the particular physiological environment in which the compositions are to be applied. Finally, U.S. patent application Ser. No. 918,532, Stone, filed June 23, 1978, discloses the use of octanoic acid as a broad-spectrum antimicrobial agent in intravenous solutions. The antimicrobial benefits are taught to be optimal when the solution pH is kept in the range 3.5 to 6.0. There is no disclosure of the topical use of octanoic acid or of formulations for such usage in this patent application.
It is an object of the present invention to provide effective topical antimicrobial compositions containing C.sub.5 -C.sub.12 fatty acids.
It is a further object of the present invention to provide effective topical antimicrobial compositions in the form of an aqueous gel or an aqueous lotion.
It is a still further object of the present invention to provide a method for the effective topical treatment of skin conditions of pathogenic origin.